The present technique relates to a biofuel cell using an oxidoreductase and an electronic apparatus. More specifically, the present technique relates to a biofuel cell having a configuration in which two or more power generating portions are connected in series or in parallel and an electronic apparatus including this cell.
Recently, a fuel cell (hereinafter, referred to as “biofuel cell”) in which an oxidoreductase is immobilized on at least one electrode of an anode or a cathode as a reaction catalyst has attracted attention. This biofuel cell can efficiently extract electrons from fuel such as glucose or ethanol which is hardly reactive with an ordinary industrial catalyst and thus has been expected as the next-generation fuel cell having high capacity and high safety.
FIG. 11 is a diagram schematically illustrating the power generation principle of a biofuel cell using an enzyme. For example, in the case of a biofuel cell illustrated in FIG. 11 in which glucose is used as fuel, the glucose is degraded by an enzyme immobilized on a surface of an anode 101 to extract electrons (e−) and generate protons (H+). In addition, in a cathode 102, water (H2O) is produced from protons (H+) transported from the anode 101 through a proton conductor 103, electrons (e−) transported through an external circuit, and oxygen (O2), for example, in the air. By allowing these reactions to simultaneously occur, electric energy is generated between the electrodes.
On the other hand, the fuel cell has a problem that the voltage of a single cell is low. In the biofuel cell, a structure in which plural cells are connected in series and/or in parallel to improve output is disclosed (for example, refer to PTLs 1 and 2). In addition, in the related art, an immersion-type biofuel cell is also disclosed in which the volume of a single cell is reduced by bringing a fuel solution into contact with an air electrode (cathode) and stacking an anode and a cathode through a separator to increase electric capacitance (refer to PTL 3).